How to plot a bar chart with several bars?

Question

I am trying to plot a bar chart in LaTeX to be displayed as below

and the script I am referring to is as below:

\begin{filecontents}{data.csv}
A,  B,  C,  D
5,  10, 17, 12
10, 9,  27, 21
15, 33, 33, 27
20, 32, 70, 69
25, 32, 102,    60
30, 44, 108,    57
35, 54, 123,    100

\end{filecontents}
\pgfplotstableread[col sep=comma,]{data.csv}\datatable
\begin{tikzpicture}
\begin{axis}[
    ybar,
    xlabel={A},
    xtick=data,
    xticklabels from table={\datatable}{A},
    ylabel={}]
    \addplot table [x expr=\coordindex, y={]{\datatable};
\end{axis}
\end{tikzpicture}

but it only displays one bar. I am very new to plotting charts in LaTeX hence any help on this will be much appreciate.

Answer 1

after convert your code sniped to worked small, complete document ...

for each bar you need add \addplot table [x expr=\coordindex, y=<column name>]{\datatable};:

\documentclass{article}
\usepackage{pgfplots, pgfplotstable}
\pgfplotsset{compat=1.15}

\begin{filecontents}{data.csv}
A,  B,  C,  D
5,  10, 17, 12
10, 9,  27, 21
15, 33, 33, 27
20, 32, 70, 69
25, 32, 102,    60
30, 44, 108,    57
35, 54, 123,    100

\end{filecontents}
\pgfplotstableread[col sep=comma,]{data.csv}\datatable

\begin{document}
\begin{tikzpicture}
\begin{axis}[width=11cm,
    ybar,
    bar width=7pt,
    xlabel={A},
    xtick=data,
    xticklabels from table={\datatable}{A},
    ymajorgrids,
    legend pos=north west
             ]
    \addplot table [x expr=\coordindex, y=B]{\datatable};
    \addplot table [x expr=\coordindex, y=C]{\datatable};
    \addplot table [x expr=\coordindex, y=D]{\datatable};
    \legend{A, B, C}
\end{axis}
\end{tikzpicture}
\end{document}